"""Map logical RGB to WS2812 wire byte order."""

from __future__ import annotations

from leds.array_config import WIRE_ORDER

# wire[i] = rgb_channel[perm[i]] where rgb = (r, g, b)
_PERM: dict[str, tuple[int, int, int]] = {
    "rgb": (0, 1, 2),
    "grb": (1, 0, 2),
    "rbg": (0, 2, 1),
    "brg": (2, 0, 1),
    "bgr": (2, 1, 0),
    "gbr": (1, 2, 0),
}


def normalize_wire_order(order: str | None = None) -> str:
    key = (order or WIRE_ORDER).lower()
    if key not in _PERM:
        raise ValueError(f"unknown wire order {key!r}; use one of {sorted(_PERM)}")
    return key


def rgb_to_wire(r: int, g: int, b: int, order: str | None = None) -> tuple[int, int, int]:
    perm = _PERM[normalize_wire_order(order)]
    ch = (r, g, b)
    return ch[perm[0]], ch[perm[1]], ch[perm[2]]


def rgb_bytes_to_wire(rgb: bytes, order: str | None = None) -> bytes:
    perm = _PERM[normalize_wire_order(order)]
    out = bytearray(len(rgb))
    for i in range(0, len(rgb), 3):
        ch = rgb[i], rgb[i + 1], rgb[i + 2]
        out[i] = ch[perm[0]]
        out[i + 1] = ch[perm[1]]
        out[i + 2] = ch[perm[2]]
    return bytes(out)


def swap_rg_bytes(rgb: bytes) -> bytes:
    """Swap R and G channels (hardware examples only — not the web simulator)."""
    out = bytearray(rgb)
    for i in range(0, len(out), 3):
        out[i], out[i + 1] = out[i + 1], out[i]
    return bytes(out)